(1) Technical Field
This invention relates to safe handling of fragile substrates, and more particularly, to a support that is suitable for cushioning various shaped receptacles containing fragile substrates during transportation.
(2) Description of the Prior Art
Protecting fragile objects such as, for example, a plurality of semiconductor wafers held in containers are further contained in a collapsible cardboard box and packed with cushioning inserts is known. In general, a cushioning arrangement for isolating fragile objects from sudden vibration and shock is acknowledged. In such an application, either a rectangular shaped or around shaped container, each holding the plurality of semiconductor wafers, is placed within a corrugated paper box arranged with a cushioning foam. Earlier methods sandwiched the container, holding the plurality of fragile objects, between a lower and upper compressible styrene or polyurethane foam layers. Each layer having either a rectangular or round recess formed large enough to receive its appropriately shaped containers, each recess having side surfaces deep enough, under compression, to cover about one half of the container. The compressed foam material presses against all of the outside surfaces of the containers, thereby, packing and cushioning the containers from all sides. Such packing within the corrugated paper box intends to prevent destruction of the container which may occur by rough handling during transportation or by an outside influence causing shock, but more importantly, to prevent breakage or the like, of the fragile items contained within.
Presently, the cushioning arrangement is molded from a soft expanded polypropylene (EPP). The cushion material is formed as two half layers that are stackable around the container with a solid bottom layer, a solid top layer, and intermediate frame shaped layer. These layers fit around the container in the general way described earlier.
Several shaped containers are used by the semiconductor industry for containing the plurality of wafers, rectangular shaped and round shaped containers are in the majority, each requiring a form fit cushion for safe transportation. That is, it is not possible to fit a rectangular shaped container in a round recessed pocket or to sufficiently secure and stabilize a cylindrical shaped container within a rectangular recess pocket.
At present, three different cushion forms are used for packing. One type is for packing a single round container. a second is used for packing a single crystal container, the third form is used for packing two crystal containers
Another disadvantage with the prior art is the increase in cost when shipping separate boxes containing specific shaped containers packed with form fitted cushions with the unlikelihood of receiving the two packages at the same time.
Presently, regulations drafted by concerned environmental agencies enforcing stringent controls towards waste products formed of styrene foam or polyurethane foam are currently in place. The problematic waste product is an important concern to global sanitation.
The present invention has been accomplished in view of the above mentioned problems. The main object of the present invention is to securely cushion both rectangular and round shaped containers containing a plurality of fragile objects using a stackable cushion design intended for cushioning only rectangular shaped containers. The cushion material is formed in two halves, a top half and a bottom half, each sandwiching the container between and around its four sides. Both halves are interchangeable, having the same form with a major top surface and a major bottom surface and four sides. A rectangular recess, having size and depth dimensions to cover about one half of a rectangular container, is centrally formed on one of the major surfaces of each half. These layers sandwich and fit around the container in the general way described in the prior art.
More specifically, the invention provides a cushion interposer to be removeably placed within the rectangular recess in each of the cushion halves, as described previously, the rectangular recesses were designed to conform to the shape of the rectangular containers. The interposer effects operative compatability between the two containers, thus providing cushioning and protection for the round container by employing one cushion design and one interposer design. The interposer is molded from a soft expanded polypropylene (EPP). This material is compressable between one thirtieth to one-fiftieth of its original volume. A further advantage of EPP, as compared with previously used materials, is that it rebounds to within about its original free state, thus making it reusable several times, thereby further reducing waste and cost. The round (cylindrical) shaped container holding a plurality of wafers, is placed into the bottom half of the interposer. The top half of the interposer is placed over the top half of the cylindrical container, which gives the outside appearance of a rectangular shaped container. The round container assembled with both interposer halves is then placed into the rectangular cavity of the cushion interposer designed to removeable fit in each of the rectangular recesses of the cushion halves, thereafter, converting the rectangular recess to a round recess. The interposer has a rectangular shaped outside form with a circumferential cavity formed therein for covering about one half of a cylindrical container.
Another object of the present invention is to reduce shipping costs by permitting the option of shipping round shaped and rectangular shaped containers within the same corrugated paper box.
Still another object of the present invention is to eliminate the need for providing a cushion specifically designed to cushion a round container.
Accordingly, the cushion interposer converts cushion structures which are designed to fit around a rectangular container, to fit and securely cushion a cylindrical container.